Re: Seeking a KVM benchmark

Wanpeng Li
2014-11-17T12:01:02Z

Hi Paolo,
On 11/17/14, 7:18 PM, Paolo Bonzini wrote:
>
> On 17/11/2014 12:17, Wanpeng Li wrote:
>>>> It's not surprising [1]. Since the meaning of some PTE bits change [2],
>>>> the TLB has to be flushed. In VMX we have VPIDs, so we only need to flush
>>>> if EFER changed between two invocations of the same VPID, which isn't
>>>> the case.
>> If there need a TLB flush if guest is UP?
> The wrmsr is in the host, and the TLB flush is done in the processor
> microcode.

Sorry, maybe I didn't state my question clearly. As Avi mentioned above
"In VMX we have VPIDs, so we only need to flush if EFER changed between
two invocations of the same VPID", so there is only one VPID if the
guest is UP, my question is if there need a TLB flush when guest's EFER
has been changed?

Regards,
Wanpeng Li

>
> Paolo